In the past, lenticular labels have tend to be as thin as possible, as thin material may most readily be made compliant with a container having a curved surface. However, this strategy is limiting, as the optical effects associated with lenticular imaging, such as animation or three-dimensionality, are limited both by the width of the lens and the corresponding fraction of the print resolution available beneath each lens. Other factors being constant, a larger lens can provide more phases of animation or more illusory depth, and can therefore gain greater consumer attention.
Speaking more generally, a larger lens can incorporate more striking optical effects and make a more effective sales device. However, such lenses tend to be proportionally thicker and therefore more difficult to apply and retain in reliable compliance with a curved container. This is particularly the case with beverage bottles such as wine, beer, or soft drinks, where labels are often applied to filled bottles that must be kept below a designated threshold temperature.
Government regulations often forbid the treatment or labeling of open bottles for fear of contamination of their contents. While ensuring consumer safety, such restrictions can further increase the challenge of providing a reliable means of adhering a label to a bottle, since the bottle cannot be overheated once filled.
Particularly, a lenticular lens sheet will, at a relatively low application temperature, be more resistant to conforming to the bottle's surface. This resistance to deflection can make the label more prone to lift at its periphery. Lenticular labels have a resolution that is limited by the lens pitch. In retail situations, lenticular lenses are typically disposed vertically, either to exhibit a depth effect, or to animate the image as a potential buyer walks past. In the case of a lenticular label, proper labeling therefore often requires a relatively generous horizontal area. However, a label that wraps around a larger portion of a bottle's transverse radius will be more prone to lifting at the edges. It may be appreciated by the foregoing discussion that the nature of lenticular materials and processes presents distinct technical demands.
While these matters are specific to lenticular printing, lenticular labels are not immune to more general issues relating to label adhesion on glass vessels, and, indeed, often exhibit more criticality.
Empty glass containers, such as beverage bottles, generally emerge from their original forming processes with smooth, continuous surfaces. Such containers, as a rule, have their greatest strength and structural integrity when newly made and free of nicks and scratches. However, just as a sheet of glass will fracture on a line after a light scoring, a glass container may be prone to break at any defect in its surface. Once initiated, such a break can cause the vessel to crack or shatter.
The manual or automated handling of untreated glass containers can bring containers' exteriors into direct contact with one another in such a way that surface imperfections result. Furthermore, sanitary automated handling equipment often sends the moving glass containers into collision with metal guides or other hard materials. Bottle transport, filling and packaging operations nevertheless require high rates of operation for economic efficiency.
Accordingly, various coatings have been developed to deter any impact or abrasion from imparting a surface flaw. Generally, these coatings prevent marring of the continuous glass surface by increasing the lubricity of the containers' vulnerable convex external surfaces. Once coated, friction between the vessel and any surface it contacts is reduced, and the microscopic blemishes that can lead to catastrophic failure are largely prevented.
It may be appreciated that materials that increase lubricity may also increase the difficulty of securely and reliably labeling a container. Therefore, deriving the right coating formulation, the correct dispersion of the coating upon the glass surface, and the optimal application method for a given combination of glass container and label structure is critical to the percentage of vessels that remain in a saleable state throughout diverse handling steps. In the case of beverage bottles these steps may include bottle transport, conveying, filling, washing, labeling, aging, boxing, shipping, storing, and vending. A label may in some cases be securely adhered by bonding it to itself along an overlapping seam. However, in the case of certain types of beverage bottles, there has been an aversion in the trade to labels of the type that by their nature wrap entirely around the bottle. An open margin along the length of the container is preferred, as it allows consumers to view the amount of its contents remaining in the vessel.
Particular budgetary challenges occur when many factors conspire to reduce the proportion of products that remain in the safe, intact and appealing state necessary to promote the sale of the item. This challenge is particularly acute, for example, in the case of beverage bottles such as wine bottles, which may be exposed to greatly and abruptly varied conditions of temperature and moisture, and which may remain in stock for years before consumption.
Prior art U.S. Patents relating to the use of curved lenticular or barrier images include U.S. Pat. Nos. 1,930,228, 2,374,371, 2,398,257, 2,810,978, 3,357,770, 3,686,781, 4,825,234, 5,365,294, 5,494,445, 5,525,383, 5,600,388, 5,642,226, 5,695,346, and 5,704,061. The methods and understandings of these inventions, and particularly those features relating to the preparation and formation of curved lenticular imagery, are hereby incorporated by reference in their entirety.
The organization CETIE publishes materials relating to the standards and practices of labeling, including beverage label application and testing, for example:    “PRESSURE SENSITIVE LABELLING ON GLASS BOTTLES AND JARS”, 2009 International Technical Centre for Bottling and related Packaging 112-114 RUE LA BOETIE, 75008 PARIS—FRANCE www.cetie.org
The standards and practices published by CETIE are also hereby incorporated by reference in its entirety.